A military flogging in the British Army.  I have to question the accuracy of the way that this "Halbert Triangle" is depicted.  Note that two of the staffs are crossed with the third fastened at the victim's knees.  Only the balance of the man being lashed would prevent the contraption from toppling forward.  From "Under The Lash- A History of Corporal Punishment in the British Armed Forces" by Scott Claver.